1. Field of the Invention
The present invention relates to a transceiver used for a wireless in-building communication system such as a high-speed wireless LAN (Local Area Network) for example, particularly to a base station transceiver for the wireless LAN, which can be easily installed to a ceiling of the building.
2. Description of the Related Art
Recently, there has been significant interest in wireless LAN which requires no rewiring due to moves, adds or changes of its terminals.
D. Buchholz, P. Odlyzko, M. Taylor and R. White, "Wireless In-Building Network Architecture and Protocols", IEEE Network Magazine, pp. 31-38, November 1991 describes such a wireless LAN. In this system, a single base station transceiver is installed at a ceiling of the building for covering a single zone. Within each zone, one or more user transceiver is disposed. Between the base transceiver and each of the user transceiver, data is transmitted via wireless network. The user transceivers do not directly communicate with one another and are connected to respective terminals such as a personal computer, a workstation and a printer via cables. The base transceiver is connected to a bus of a main processor and a main memory in the base station via a cable. Thus, between the base transceiver and the bus, data will be transmitted via the cable.
In such wireless LAN, it is required to install the base transceiver at the ceiling of the building so as to obtain good transmission performance. However, in most of existing buildings, especially in buildings for offices, department stores or restaurants which have a great demand for the wireless LAN, it will be impossible to execute construction for installing the conventional base transceiver to the ceiling. Even if the base transceiver can be attached to the ceiling, difficult construction for wiring, in the ceiling or along the surface of the ceiling, a data transmission cable connecting the base transceiver with the base station is required. Also, in order to supply commercial AC power to the base transceiver installed at the ceiling, it is necessary that a power supply cable is wired in the ceiling or along the surface of the ceiling from an existing electric outlet to the base transceiver or that an additional outlet is constructed near the base transceiver by making a hole through the ceiling. Furthermore, since the base transceiver is so heavy in weight (e.g. about 3 Kg) that most ceilings cannot sufficiently support it, the position at which the base transceiver will be attached may be restricted or in some cases construction for reinforcing the ceiling may be needed.
Labor and material costs for wiring the cables and for reinforcing the ceiling will be significant, particularly when the number of the base transceivers is great, the costs will increase extremely. According to the conventional wireless LAN system, furthermore, these wiring and reinforcement are required even if the system is temporarily installed only when council or exhibition is held.